Rapamycin induces apoptosis of lung adenocarcinoma cell A549 under hypoxia and its molecular mechanism
10.3781/j.issn.1000-7431.2010.04.006
- VernacularTitle:雷帕霉素联合缺氧诱导肺腺癌A549细胞凋亡及其分子机制
- Author:
Bin CHEN
;
Weiqing GU
;
Jian NI
- Publication Type:Journal Article
- Keywords:
Carcinoma,non-small cell lung;
Adenocarcinoma;
Sirolimus;
Hypoxia-inducible factor 1;
Cell,A549
- From:
Tumor
2010;(4):293-297
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the molecular mechanism underlying apoptosis of lung adenocarcinoma cell line A549 induced by rapamycin, a type of mammalian target of rapamycin (mTOR) signal pathway inhibitor, combined with hypoxia treatment. Methods:Rapamycin was applied to treat A549 cell line under hypoxia for 16 h. Then the discrepancy of cell apoptosis between treated and untreated control was compared by Hochest 33258 staining. After being treated with rapamycin combined with hypoxia, the mRNA and protein expressions of survivin, a kind of anti-apoptotic molecule, were tested by real-time PCR and Western blotting. Western blotting was employed to test the difference of hypoxia-inducible factor (HIF)-1α expression level before and after rapamycin was added. In additon, chromatin immunoprecipitation(ChIP) assay was further applied to explore the mechanism underlying the effects of rapamycin under hypoxia in inducing apoptosis of A549 cells. Results:Rapamycin induced apoptosis of A549 cell line under hypxia in vitro. In A549 cell line, the expressions of survivin at mRNA (P<0.01) and protein levels, were both decreased by rapamycin combined with hypoxia treatment. Besides, ChIP assay revealed that rapamycin inhibited the expression of survivin at the transcriptional level through decreasing the hypoxia-induced up-regulation of HIF-1α and its binding with the promoter of survivin gene. Conclusion:Rapamycin exerted anti-tumor effects by inhibiting the expression of HIF-1α and decreasing the binding of HIF-1α with the promoter of survivin gene, thereby down-regulating the increase in the expression of apoptosis inhibiting gene survivin.
